I have oil in the coolant but do not have coolant in the oil? Any ideas? Thanks.

 

only thing i can think of is if you have a trans cooler with lines going to the radiator ,the older car's and truck used to have a pancake cooler in the radiator that some time,s would leak oil into the radiator .
then the later models started coming with external coolers .

 

I have a 2000 Chevy truck I think the cooler seal is leaking water into the transmission.

 

could be head gasgket

 

I would be checking the engine oil cooler if it has one in the rad or the trany cooler. I would not jump to the head gaskets. Check the simple things first. Is it engine oil or trany oil? It might be hard to tell if the trany oil is dark but I would suspect a cooler issue.

 

I don't believe a head gasket will allow water into the transmission.

Unless you drove through some water that was up to the vent or someone just poured water in through the filler tube, most likely sucking coolant into the transmission through the radiator. Only ways I ever heard to get water in the transmission. (if you have an Automatic transmission).